Remote control system



0d. 6, 1936. s LANYON 2,056,282

REMOTE CONTROL SYSTEM Filed Jan. 8, 1934 INVENTOR, SAMUEL H. LA/VVO/V. W4

. ATTORNEY Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE 6 Claims.

My invention relates to electrically operated remote control systems.

Among the objects of my invention are: To provide a remote control system which permits, at option, manual operation, semi-automatic operation, or full automatic operation for controlling devices requiring adjustment at spaced intervals of time; to provide a remote control system which is adapted to control any apparatus 10 normally controlled or operated by a movable element; to provide a flexible means for control ling certain types of apparatus; and to provide a simple and eflicient remote control mechanism.

Other objects of my invention will be apparent or will be specifically pointed out in the description forming a part of this specification, but I do not limit myself to the embodiment of the invention herein described, as various forms may be adopted within the scope of the claims. Referring to the drawing:

Figure l is a diagrammatic view of the apparatus and control circuits comprising the remote control system of my invention.

Figure 2 is a circumferential development of one of the contactors'.

Broadly considered, my invention comprises the combination with an element to be controlled, (which may be typified by the tuning shaft of a radio receiver) of a reversible motor for driving said element. Positively driven by the controlled element are a plurality of pole changers or commutators, each of which is provided with an insulating sector which interrupts the current between reversals thereof, and these insulating sectors are positioned respectively to interrupt the current at different desired positions of the controlled element.

Switching means, periodically operative, are provided for connecting a desired one of the pole changers to the reversible motor, so that the motor will drive the controlled element in the proper direction to bring the insulating sector under one of the pole changer brushes, whereupon the interruption of current will stop the motor. These means comprise a plurality of selector switches, operable momentarily at the beginning of each interval, one being associated with each pole changer, and an element movable in relation to time, which is adapted to actuate, at said time intervals, a selected one of the selector switches to effect rotation, by the motor, of the particular pole changer associated with that switch.

Means are also provided, operative in conjunction with the selector switches whereby the selector switches are permitted to operate to connect others of the pole changers to the switching means to cause a change of position of the controlled element, or whereby maintenance of the previous position of the element may be had for successive time intervals. These comprise a trip 5 switch, which operates interchangeably with the selector switches to control the switching means, so as to de-energize the previously actuated switching means at the end of a time interval, should it be desirable to actuate another of the 10 switching means, or which is deactivated by the operation of a selector switch, to permit continuance of actuation of the switching means for successive time intervals.

Manually operative switching means are also 15 provided which permit automatic periodic actuation of the pole changer switching means, or which permit selective actuation thereof for periods, the extent of which is at the option of the operator. 20

Automatic remote control systems find a wide field of utility in installations such as radio broadcast stations, where telephone trunk lines carrying programs emanating from distant points, are cut in to the transmitter at specified 25 time intervals, in radio receiving stations where watch must be maintained periodically on a plurality of wave channels, in the control of street lighting systems, and in numerous like instances where apparatus is time controlled.

An urgent need has been felt in the art for a remote control system, for such mechanisms, which is simple and reliable in operation, contains a minimum of operating parts, and is adaptable to a wide variety of such apparatus 5 requiring adjustment at periodic intervals.

For the most part, the devices, for such purposes, in present use, are complicated, and costly to construct and maintain. The ideal control system is one which is adaptable for operation 40 with any device that is normally controlled manually by means of a movable element or controller. Such a system should be capable of being rendered inoperative to permit such manual control, or of being connected to provide semi-automatic or 45 automatic operation. Means should also be included in the system for permitting the control thereof at predetermined intervals of time and such means should be readily adjustable.

I have provided a system of the character de- 50 scribed which incorporates all of these desirable features, is not likely to get out of order, and is easily constructed and economical in operation.

While the apparatus I am about to describe may be used, with slight modification, for all of the 55 uses mentioned above, and many others, I prefer to describe its use in connection with radio receivers as a means for automatically selecting desired programs, at intervals, over an extended period of time.

A great number of radio listeners have one or more favorite programs or are followers of one of several features presented in serial form. In a great many instances, due to preoccupancy of the person with other matters, these programs are in part or wholly missed, with the result that the continuity of the story or program is interrupted in the listeners mind; in some cases the unheard part being vital to the complete understanding or enjoyment of the presentation. I have provided a device which may be connected to, or incorporated in, radio receivers by means or which selected programs, over an extended time interval, are automatically tuned in, thereby eliminating the possibility of missing any portion of these programs' Describing my invention in greater detail, and referring to Figure l of the drawing, I provide a shaft 2, which may be connected to a radio receiver tuning shaft 3, by means of suitable gearing 4, or by any other positive mechanical means. The shaft is provided with commutators or pole changers 5 and 6, each being insulated from the shaft by an insulating bushing l, and each comprising, in its preferred form, a pair of spaced cylindrical drums 8 and 9 which are provided with offset portions I I and !2, so that each drum has three circumferential zones I3, i4 and E6; the outer zones being continuous about the drums and the inner zone being interrupted at points I? by insulating material E8. The foregoing construction is clearly illustrated in Figure 2.

A plurality of current-carrying brushes i9, 2i], 2] and 22, are spaced about, and in contact with, the drums; two of the brushes 2i] and 22 engaging the center zone, the outer zones each being provided with a single brush l9 and 2!. With reference to Figure 2, it will be seen that a conductive path is provided between two sets of brushes I320 and 2i-22 by the metallic drum sections. Rotation of the drum, so that the brushes 2!) and 22 are caused to ride upon the insulating material at the points i1, causes both conductive paths to be broken, while further rotation of the drum will provide a conductive path between the'brushes i9 and 22 and another between the brushes 23 and iii, thereby reversing the relationship that existed therebetween in the first instance. While the preferred form of contactor drum is that just described, which allows 180 of rotation of the shaft 2, I may prefer to use a drum comparable to the center zone E4 of the contactor illustrated, in that the drum periphery is divided into two sections, separated by insulating points ill. The brushes, in this case, may be disposed about the drum in vertical planar alignment instead of being staggered as shown in Figure 2. This construction, it will be observed, permits only of usable drum rotation, however the rotation of the shaft 3 may be multiplied or reduced by choosing a suitable ratio for the gearing 4. Brushes l9 and 2i may be replaced by flexible conductors if preferred,

Means are provided for imparting rotary movement to the drums which comprise a reversing motor 23, having a worm 24 on the shaft thereof, which meshes with a worm gear 26 rotatably mounted on the shaft 2. A solenoid-operated clutch, comprising a hub 27 mounted on the gear, and a sleeve 28, slidably keyed to the shaft 2 and adapted to be frictionally engaged with the hub 21 through the medium of the armature 29 actuated by the winding 3! in parallel with the main motor line, is provided for engaging the driving means with the shaft.

The particular arrangement of the circuits and the cooperative relationship between the various parts, to be described in detail later, is such that when certain circuits are energized through one of the drum contactors, the. motor rotates in a direction depending upon the relationship of the brushes on the drum until the circuit is broken by virtue of the brushes reaching the insulated points ll, whereupon the motor will stop. Each drum may be given a different setting, representing various angular displacements of the shaft, by adjusting their positions by means of the set screws 32. It will be obvious that these angular displacements may be made to coincide with degrees of rotation of the receiver tuning shaft 3 for the purpose of automatically tuning-in a selected one of as many stations as there are drum contactors on the shaft. While I have chosen to illustrate my invention with but two drums, to obviate unnecessary complication of the drawing and description, it will be understood that any number of drums may be used, depending on the number of stations it is desirable to control.

Switching means are provided for connecting a desired one of the pole changers to the motor. These means comprise relays 33 and 34, one for each pole'changer, each having three coils, namely, a field coil 36, a hold-in coil 31, operative only during full automatic control, and a selector coil 38. The coils are so proportioned that energization of either one of the coils 37 and 38 is required, together with energization of the field coil 36, in order to produce sufiicient magnetic flux to actuate the relay. However, once the relay is closed, all but the hold-in coil may be de-energized, either this coil or the selector coil being capable of holding the relay closed without the aid of the field coil 36. One end of each of the coils is connected electrically with a lead 39 which connects with one end of the secondary coil of a transformer 43 and with the rotor of the reversing motor 23.

Another lead 42, is provided, connecting the other end of the transformer secondary coil with one contact of a pair of contacts 43 connected with the relay 33 and with another of a similar pair of contacts 44 connected with the relay 34. A lead 46 connects the other contact 43 of the relay 33 with the brush 20 of the pole changer 5 and the other contact 44, of relay 34, is connected by the lead 4'! with a corresponding brush 20 of the pole changer 6. For example, it will be seen that if the coils 3'! and 38 of the relay 34 were energized the contacts 44 will be closed and will permit current to flow in the lead 41 to the brush 23 of the pole changer 6. Current will then flow through the conducting surface of the drum 9 to the brush 2! and thence by the lead 48, through the motor field coil 49, through a lead 5|, connecting the field coil with the brush 19, through the conducting surface of the drum 8 to the energized to connect the gear 26 for rotation with the shaft 2. Assuming that the relation of the brushes is such that the motor will drive the gear 26 in a clockwise direction, the pole changer 6 will be rotated, as indicated by the arrow, until the insulated portion l1 thereof reaches a position under the brush 20 and the corresponding insulated portion reaches a position under the brush 22. When this occurs the motor circuit will be broken and the pole changer will stop rotating, coming to rest in a position corresponding to the angular displacement of the shaft 3 required to tune-in the desired station.

Similarly, when it is desired to tune-in the station corresponding to the pole changer 5, energization of the relay 33 will close contacts 43 and permit current to flow in the lead 46 to the brush 20 of the pole changer 5. As before, the motor will be started and will rotate the pole changer until its insulated portions reach positions under the brushes 20 and 22 of pole changer 5 whereupon the motor will stop having caused rotation of the pole changer to the position required to tune-in the station with which it is associated.

It will be noted, that if pole changer 5 is the first one selected, the movement thereof will cause the insulated portions of the pole changer 6 to move beyond the brushes 20 and 22. This reverses the polarity of the brushes with the result that when the circuits connected with the pole changer 6 are energized a reversed motor rotation will be caused which will rotate the pole changer in a counter-clockwise direction until the insulated portions reach positions under the brushes when the motor and pole changer will stop as before. It will be seen, therefore, regardless of which of the stations is selected, its associated pole changer will cause rotation of the shaft 2, by the motor, in the proper direction and to the correct angular displacement required to tune the station in.

Means are provided for selectively energizing the pole changer switching means at predetermined intervals. A chart 55 of paper or other insulating material, having indicia 56 thereon, is provided at one edge with perforations 51, with which the teeth of a drive sprocket 58 are adapted to mesh. The sprocket is provided with, and insulated from, a shaft 59, having a sprocket 6| thereon which is connected by a chain 62 with a sprocket 63. This sprocket is carried by a shaft 64 connected, through suitable reduction gearing 55, with the rotor of a synchronous clock motor ill. The coil of the motor is constantly energized from leads 88 connected to a source of synchronized alternating current 59. If direct current is available instead of alternating current, a mechanical clock movement may be substituted for the motor 61.

The motor 61 is of the type used in electric clocks and is preferably of the character which is self-starting and provided with an auxiliary spring mechanism which permits the motor mechanism to run for a time should the electric current be interrupted. By means of the apparatus just described, the chart is moved at a uniform speed related with time, and the chart may be set off by lines II to indicate certain divisions thereof. Only a portion of a chart is shown in the drawing; this being done to conserve space, it being understood that the chart may be endless or of any length and may be provided with spools on which it may be wound. Overlying the chart are one or more resilient conductive fingers I2 and 13 provided with turned ends which are adapted to press against the face of the chart.

As the broadcasting time of most stations is divided into fifteen minute intervals, I provide means for permitting selection of programs at such intervals, either by automatically shifting from one program to another or continuing with the same program for any desired multiple of the unitary fifteen minute period. To attain this end, holes such as 14 and 16 may be punched in the chart on the station lines 11 and 18, to permit electrical contact to be made therethrough between the fingers 12 and I3 and the sprocket 58, when holes pass under the turned ends of the fingers.

As the rate of movement of the chart, and consequently the time value between each line H is constant, and equal to the interval between operations of the trip switch 83, it is necessary to space the punched holes in the chart a distance apart, determined by these lines, one hole being punched for each fifteen minute interval that it is desired that the program from a certain station be sustained. The indicia 56 may be used to provide a visual aid in locating the holes. It is to be understood that the vertical position of the hole determines the operation or non-operation of the receiver during the following time interval, while the lateral position of the hole determines, through its relation with the proper contact finger (l2'l3) the station to be selected at that time.

For the purpose of selecting the desired mode of operation of the device, i. e., automatic, semiautomatic, or manual, a plurality of control circuits are provided, the main parts thereof comprising the transformer 4|, a selector switch 19, relays 8| and 82, and a trip switch 83, the latter being operated by a cam 84 mounted for rotation with the shaft 64, and preferably insulated therefrom.

The selector switch 19 has four positions, namely, A, wherein the remote control system may be rendered inoperative while permitting the usual manual operation of the receiver; position B which conditions the circuit for full automatic operation, and positions typified by positions C and D which cause semi-automatic operation of the receiver, i. e., any selected station is automatically tuned-in by manual operation of the switch to a corresponding one of these two latter positions.

Tracing a control circuit in greater detail, let us assume that the selector switch is in the automatic selecting position or position B, as shown in Figure 1, and a hole ?8 has, by movement of the chart, been brought into position below the end of the finger 13. With the hole in this position, contact is established therebetween and the sprocket 58, permitting current to flow from the low potential secondary winding of the transformer 4! through the lead 39, the selector coil 38 of the relay 34, and through lead 86 to the finger 13. The return circuit from the sprocket passes through a brush 8?, a lead 88, through the winding 89 of the relay 8|, and through leads 9| and 92 to a selector switch contact 93. The circuit is continued through the conductive arm 94 of the selector switch, through an arcuate contact bar 96, and leads 9! and 42 back to the transformer Al. The energization of this circuit closes relay 8|.

When the relay closes current is taken from the energized lead 9|, through the relay contacts, and by the lead 98 to the normally closed contacts 99 of the relay 82. The circuit is continued from the relay through a lead H, which connects to both field coils'36 of the relays 33 and 34, and through these coils to the lead 39. Since both the selector coil 38 and the field coil 36 of the relay 34 are now energized, this relay will close and permit energization of the pole changer circuits as explained above. Even though the field coil 36 of the relay 33 is energized this relay will not be operated since only one of its coils is energized.

Since the contact between the finger l3 and the sprocket 58 is of short duration it will be seen that means must be provided to prevent opening of the relay when the selector coil 38 is deenergized when its circuit is broken. This is accomplished by transferring control of the relay from the selector coil to the hold in coil 31. A pair of contacts I92 are provided on each relay 33 and 34 and when these contacts are closed a circuit is established comprising the lead I93 which feeds back through the primary winding of the receiver power transformer I94, and the lead I96, to one leg of the power source 69. A lead I07 which connects to the winding 93 of the transformer 4!, and to the coil I98 of the relay 82, continues as the lead I 09 to the contacts I92 of each relay 33 and 34.

Energization of this circuit causes the relay 82 to lift and connect a pair of contacts I I I. This establishes a circuit from the lead 9|, through the lead II 2, through the contacts III, lead H3, trip switch 83, leads H4, coils 31 of each relay, and back to the transformer by way of the lead '39. Since none of the coils of relay 33, with the exception of coil 31, are energized, this relay will not be effected, but since relay 34 is already closed the holding-in of the relay is performed by both coils 3'! and 38 until the chart, by its movement, breaks contact between the finger and the sprocket, whereupon coil 38 will be de-energized thereby leaving the holding-in of the relay to the coil 3'1.

The trip switch 83 is in series with this hold-in coil, as well as the others of the various selector relays. The function of this switch is primarily to time the operation of the automatic control, for it will be seen that a switch of this type may be set to operate with extreme accuracy with respect to the position of the clock shaft. The position of the holes in the mask 55 is subject to variation in position which might cause several minutes difference in the time of operation in the control apparatus, but since no succeeding automatic operation can occur until the hold-in circuit is broken by operation of this switch, exact timing is achieved.

Furthermore, since the exact positioning of the holes in the mask is not relied on for timing, these holes are preferably made large enough so that the fingers I2, I3, etc., may make contact a sufiicient time before the beginning of each program period to permit the tubes to heat (if not already active) before the program selected starts.

If it is desirable to continue reception of the same program, without interruption for consecutive periods, a hole I I9, shown by the dotted line on the station line I8, may be provided to prevent opening of the relay 34 at the end of the fifteen minute interval. When this hole comes into registry with the end of the finger '13, which is timed to occur prior to the opening of the trip switch by the cam 84, the relay coil 38 is again energized as described above and serves to hold the relay 34 closed during the momentary deenergization of coil 3! due to-the opening of the trip switch. As soon as the switch again closes, the coil 3'! will be re-energized and the coil 38 will later be de-energized, due to the movement of the chart to break contact between the finger 13 and the sprocket 58, with the result that the closed relay 34 will not be affected. The program will thus be sustained for ,an additional. fifteen minute period. 'It will be seen that by the addition of holes on the station line 18, this sustaining of a particular station maybe continued as long as desired. i

Assume, however, that at the end of the fifteen minute period, it is desirable to tune to a station whose indicating hole I I! appears on the station line 77 and which is'related with the pre-positioned contactcr 5. When the trip switch 83 is opened at the end of the period, the relays 34 and 82 will open, due to the absence of a sustaining hole on the chart, and the relay 33 will close due to the current flowing through the finger I2, by virtue of the contact permitted by movement of the hole I I! under the end thereof, through a lead H8, and the winding 33 of relay 33 back to the lead 39. This closes the relay 8i as before, which energizes the coil 36, thereby closing relay 33. Contacts I92 of this relay close and effect closing of the relay 82, which de-energizes the coils 36, and by closing contacts I I I energizes coils3'l which serve to maintain the ..relay in closed relation when the coil 38 is de-energized due to breaking of the circuit therethrough when the hole II? passes the end of the finger 12. If, due to error, holes are punched in more than one station line, thereby causinga low resistance circuit to the motor by the: closing of more than. one relay, a fuse I 59 or equivalent circuit breaker may be provided in the lead 42 for protecting the motor against damage. Closing of relay contacts 43 will causethe motor to drive the pole changer as described above.

I have thus explained how it is possible, with the remote control apparatus of my invention, to automatically control radio receivers or like devices, over predetermined intervals of time. It is quite obvious that the length of time through which this control may be obtained is governed by the length of the chart; it being a comparatively easy matter to provide a chart of such dimensions as to extend this time over a period of a week, month, or longer. Continuous repetition of oper ation may be obtained by providing an endless chart representing, for example, a period of twenty-four hours.

Means are also provided for permitting semiautomatic operation of the receiver. The selector switch l9 is provided with contacts i2! and I22, the former being connected by a lead I23 with the lead I Hi and the latter being connected by a lead I24with the lead 89. Manual operation to move the switch arm to the position C will cause current to flowfrom the transformer 4|, through leads 42 and 9?, bar 96, conductive arm 94, lead I23, lead I26, and coil 38 of the relay 33, back to the transformer by way of the lead 39. This energizes coil 38 of the relay 33. Current is also taken from the bar 99, through the arm 94, through the bar. I21, lead I28, normally closed contacts I29 of relay 82 and thence by the lead MI through the coils 33 to'the lead 39. Energization of both of these coils of the relay 33 will close it, whereupon the relay 82 is raised, de-energizing coils 3B. As the automatic selector circuits are now inoperative due to movement of the arm 94 fromthe contact corresponding to position A, the relay coil 31 will not be affected, the coil 38 alone serving to hold the relay 33 closed as long as the arm 94 is in contact with the contact I2 I. Relay contacts 43 will be closed by energization of relay 33 and will cause rotation of contactor 5, as described in connection with the automatic operation. Similarly, movement of the arm to position D will energize the coil 38 of the relay 34, and institute the sequence of events recited above, with the result that the contactor 6 is moved to tune in its related station. When it is desired to render the remote control inoperative, the switch arm is moved to. position A whereupon contact is made between terminals I3I and I32 through the conductive arm I33.

It is desirable, so as not to change the current value flowing through the primaries of the transformer 4| and the receiver power transformer I04, and to keep these values constant, to provide an impedance I34 which matches the impedance of the winding I08 of the relay 82, and replaces this winding when it is disconnected from the power circuit when the selector switch is thrown to position A.

While I have described the use of the remote control system of my invention with a radio receiver, other uses, within the scope of the claims, will be apparent to those skilled in the art; a few of these being the combined automatic, semiautomatic, or manual control of electric sub-stations, street lighting systems, illuminated sign boards, automatic elevators, both for controlling and leveling the same, coin operated radio receivers wherein a separate coin slot may be provided for selecting each station, and for numerous other apparatus whereof control is desirable at predetermined intervals.

In this regard it should be noted with reference to the pole changer assembly that if brushes 2| and 22 were to be mounted so as to be circumferentially movable around the pole changer assembly and adapted to be manually or otherwise moved around the circumference, and that if the brushes 2I and 22 are placed in a circuit which will control motor 23, that the pole changers 5 and 8 will follow the movement of the brushes 2I and 22 until they come to rest on the insulated barriers Iii-I8. In this manner it can readily be seen that by the use of two synchronous motors in parallel, one being the motor 23 and the other being connected to distant apparatus, remote control may be had of this apparatus. Other ap plications of the device will be appfirent to those skilled in the art.

I claim:

1. In a remote control system comprising a power source, a shaft adapted to be connected with apparatus to be controlled, means for rotating the shaft, a plurality of control circuits connecting the power source and the shaft-rotating means, a relay in each control circuit for controlling the shaft-rotating means, each relay comprising more than one actuating coil, means associated with the control circuits for permitting energization of a plurality of said coils to close the relay, means for permitting de-energi-- zation of all but one of the coils to permit the relay to be held closed by said remaining energized coil, and means interposed in said coil circuit for (lo-energizing said coil at spaced intervals.

2. In a remote control system comprising a power source, a shaft adapted to be connected with apparatus to be controlled, means for rotating the shaft, a plurality of control circuits connecting the power source and the shaft rotating means, a relay in each control circuit for controlling the shaft rotating means, each relay comprising more than one actuating coil, means including a time controlled switch operable at predetermined intervals for permitting energizaticn, at said intervals, of a plurality of said coils to close the relay, means for permitting deenergization of some of said coils to permit the relay to be held closed by the remainder of said coils, and means interposed in the circuit of said remaining coils for deenergizing the coils at spaced intervals.

3. In a remote control system comprising a power source, a shaft adapted to be connected with apparatus to be controlled, means for rotating the shaft, a plurality of control circuits connecting the power source and the shaft rotating means, a relay in each control circuit for controlling the shaft rotating means, each relay comprising more than one actuating coil, means including a time controlled switch operable at predetermined intervals for permitting energization, at said intervals, of a plurality of said coils to close the relay, means for permitting de-energization of some of said coils to permit the relay to be held closed by the remainder of said coils, and time controlled means operating in synchronism with said time controlled switch, and interposed in the circuit of said remainng coils, for (ls-energizing the coils at spaced intervals.

4. In a remote control system comprising a power source, a shaft adapted to be connected with apparatus to be controlled, means for rotating the shaft, a plurality of control circuits connecting the power source and the shaft rotating means, a relay in each control circuit for controlling the shaft rotating means, each of said relays including a plurality of actuating coils, means including a time control switch for energizing a plurality of said actuating coils to close said relays at predetermined intervals, and means for actuating the shaft rotating means by operation of said relays and for preventing deenergization of said relays when only a part of said plurality of coils is energized.

5. In a remote control system comprising a power source, a shaft adapted to be connected with apparatus to be controlled, means for rotating the shaft, a plurality of control circuits connecting the power source and the shaft rotating means, a relay in each control circuit for controlling the shaft rotating means, a switch comprising a pair of contacts, in circuit with each of said relays, a chart of insulating material movable in relation to time between said contacts and adapted to normally hold said contacts apart, said chart having apertures therein, spaced according to intervals of a prearranged time schedule, through which electrical connection may be made between said contacts when said apertures are moved into alinement therewith, and a trip switch, also in circuit with said relays, and operable to permit de-energization of a relay in the absence of an aperture in the chart corresponding thereto at the end of a time interval, or for preventing de-energization of said relay at the end of said time interval in the presence of an aperture in the chart corresponding thereto.

6. In a remote control system comprising a power source, a shaft adapted to be connected with apparatus to be controlled, means for rotating the shaft, a plurality of control circuits connecting the power source and the shaft rotating means, a relay in each control circuit for controlling the shaft rotating means, a switch comprising a pair oi contacts, in circuit with each of said relays a chart of insulating material movable in relation to time between said contacts and adapted to normally hold said contacts apart, said chart adapted to be manually pierced to provide apertures therein spaced according to intervals of a prearranged time schedule and through which electrical connection may be made between said contacts when said apertures are moved into registry therewith, and a selector switch operable during a short interval at the conclusion of each time interval for permitting de-energization of said relay in the absence of an aperture in said chart for indicating selection of said relay during a succeeding time interval, or for preventing de-energization of said relay in the presence of an aperture therein.

SAMUEL H. LANYON. 

